Do you remember solar startup Solexant? The firm went silent about two years ago.

But the firm is back and unstealthing.

Damoder Reddy founded the startup in 2006 along with Prof. Paul Alivisatos of UC Berkeley. The company raised more than $60 million from Olympus Capital Partners, DBL Investors, Birchmere Ventures, Trident Capital, Firelake Capital, and Medley Partners. At the time Reddy said that the firm was synthesizing "semiconducting nanoparticles" on a "scale never done before." The cadmium telluride (CdTe) nanoparticles were applied to a flexible metal foil substrate, roll-to-roll, using an ink-type solution.

In June 2011, Brad Mattson, Silicon Valley mover and shaker, took over the CEO reins. Founding CEOs parting with their VC-funded, thin film startups is more the rule than the exception and has occurred at MiaSolé, Nanosolar, HelioVolt, Solyndra, SoloPower, etc.

Mattson was the CEO and founder of Mattson Technology and Novellus Systems and an executive and entrepreneur in the semiconductor equipment industry. He spent a little over a year as a partner at VC firm VantagePoint Venture Partners where he focused on solar firms.

Today Mattson is unstealthing Solexant along with declaring his vision of what the solar industry will look like over the next decade. Mattson has lived through a number of semiconductor business cycles and sees the solar industry at the beginning of a long growth curve.

We spoke with Mattson last week. He noted that when he came to the firm, "Solexant was in the same mode as Solyndra, MiaSolé, Nanosolar, etc. -- rushing headlong into full production."

Mattson and the board canceled everything. They pulled the plug on Solexant's 100-megawatt Oregon factory, and "that saved the company," according to Mattson. He also tripled the R&D budget.

Mattson had looked at over 200 solar startups while at VantagePoint and at Solexant, and went about studying the solar materials systems and processes with a relatively blank sheet of paper. At one point, the firm was investigating five materials systems. Solexant acquired the remains of Wakonda (GaAs), set world records in CZTS, and worked further with CdTe. All of this was in the service of making thin-film solar cheaply.

The ultimate conclusion was co-evaporated CIGS in a roll-to-roll process because it's "higher efficiency than anything else." NuvoSun, a CIGS firm recently acquired by Dow, uses a high-speed roll-to-roll sputtering process on flexible foil.

"The challenge isn't the science. It's an equipment challenge. It's engineering. And it can be done."

Having looked at every solar manufacturing method and determining that "process simplicity is crucial," he also noted that "process complexity killed Nanosolar." (Although Mattson liked Nanosolar's focus on speed.) 

Mattson sees Solexant as combining the highest efficiency science with the highest tool capability. It has to be "repeatable and fast." Mattson sees the thin film industry populated by five players within a few years, none of which will be Solar Frontier.

Mattson realizes the challenge in CIGS, saying, "CdTe wants to go together well. CIGS is the opposite -- the materials want to do many things. It's difficult but allows for concentration gradients. You can dope CIGS -- but it is more of a challenge to control." Solexant has also studied the tradeoffs between singulating cells and monolithic deposition.

Mattson looks to "apply semiconductor process control" and "focus on speed," with a minimum line size of 250 megawatts and one that is as fully automated as possible.

As far as market entry, Mattson is not in a rush, asking, "Why would you enter this market while it's rationalizing?"

Mattson is looking to build an all-star thin-film solar team. He sees thin film firms as materials companies, equipment companies, and device companies, and believes this has killed a number of solar startups. "This business requires three or fours stars -- it's like three or four businesses in one. You need an equipment CEO, you need a solar CEO, and you need a device CEO."

Mattson sees the solar industry as being in the "gigawatt era" -- but the idea with thin film is to build that gigawatt in a 10,000-square-foot factory, not a 200,000-square-foot factory.

As part of Solexant's unstealthing, the firm announced that Jim Woolsey, former Director of the CIA, has joined its Board of Directors. Woolsey has limited expertise in solar, equipment, semiconductors, and materials, but he is a believer in and a promoter of renewables for economic and security reasons.

Mattson also predicts that China, in the midst of "a dozen Solyndras" with crystalline silicon, is looking to thin film as the future (although Hanergy is running into some troubles with its thin film aspirations, according to Caixin Online).

The next year is about raising capital for Mattson, and that capital might come from the Silicon Valley of the U.S. -- or the Silicon Valley of China.

Mattson declared, "We want to be the lowest-cost producer in Solar 2.0."

Tags: brad mattson, cadmium telluride, cdte, cigs, damoder reddy, heliovolt, miasolé, miasole, nanosolar, roll to roll, roll-to-roll, solexant, solyndra, thin film, thin film pv